The present invention generally relates to a shield cover, and more particularly, to an integrated type of metallic shell which is adapted to almost completely surround, flex a connecting portion between a shielding wire and a connector including a non-shielding district between a pressure fixing terminal portion and a shield processing portion so as to effect the shielding operation.
Recently, shielding wires are often used, as internal wiring for electric or electronic appliances, so as to remove influences of high frequency pulses, electromagnetic waves and vibrations. In motorcars where, for example, engine controls and so on are effected by computers called ECUs, signals from each type of sensor are fed to the ECU, each type of control of engine controls and so on are adapted to be effected in accordance with these signals. Wirings for connecting with the ECU often extend through the engine room and are subject to influences of engine vibrations, high frequency pulses and so on in the extension of the wirings through the engine rooms. In order to remove the influences, shielding wires are used.
As shown in FIG. 8, the periphery of a core 3 (hereinafter referred to as electric wire 3) with a core wire 1 being coated with an outer cover 2 is surrounded with a shield 4 which is a braided member of soft copper wires. The periphery of the shield 4 is coated with a housing 5 for insulation.
When a shielding wire 10 with many electric wires 3 being collected is used as a wire harness for motorcar use, the housing 5 is removed at its tip end by a given size as shown in FIG. 8 when the above-described shielding wire is connected with a connector. The shield 4 exposed in the housing removing portion is untied and intertwisted so as to form a connecting portion 6. Respective electric wires 3 are branched. The tip end of each electric wire 3 is also removed in outer cover 2 so as to expose the core wire 1. As shown in FIG. 9, a pressed terminal 7 is mounted to the core wire 1. The pressure fixing terminal 7 is inserted into each terminal accommodating chamber 82 of the connector housing 8 and is connected with the other party connector (not shown).
In the above-described connector connecting portion, the shield 4 is removed across the wide range from the terminal so as to branch the electric wire 3. In the pressure fixing portion with respect to the pressure fixing terminal 7, the core wire is exposed, so that the non-shielding district is wide, where the shield effect is almost equal to nothing.
Conventionally, the connector housing is surrounded with a metallic shell which is bent so as to effect the shielding operation. A connecting portion 8 composed of the above-described shield 4 is connected with the metallic shield so as to effect the shield processing operation.
A division type composed of a pair of metal shells 9 - I, 9 - II as shown in FIG. 9 and an integrated type composed of one metallic shell 9 as shown in FIG. 10 and FIG. 11 are provided as a shield cover composed of the above described metallic shield.
When the above described division type of shield cover is used, the connector housing 8 is covered, and the portion of the branched electric wire 3 which is not shielded by the shield 4 and which extends externally from the connector housing 8 can be completely covered, thus improving the shield effect.
But a pair of metallic shells made of two members are required, and they are required to be connected with each other, increasing the number of the parts, and the number of the assembling steps, with a problem of higher cost.
When the above described integrated type of shield cover is used, an opening portion is required rearwardly on the electric wire insertion side so as to insert it with ease in a case where a connector housing, into which the pressure fixing terminal of each electric wire tip end of the shielding wire is inserted, is set into the interior of the shield cover. A terminal 7 fixed under pressure to each electric wire 3 may be inserted into the terminal inserting chamber of the connector housing 8 set in advance into the shield cover interior. In this case, it cannot be inserted without the above-described opening portion. Therefore, the range of (A) in FIG. 11 cannot be shielded.
The shield cover composed of the conventional integrated type of metallic shell 9 has the front portion in the form of a bell portion 9a which surrounds the whole front outer peripheral portion of the connector housing 8 to be connected with the other party connector, and the rear portion including the top face with the opening portion 9b.
In the above described integrated type shield cover, there are advantages in that the engagement bother which is necessary in the division type can be omitted or the like. Since the connector housing or an opening portion 9b for terminal insertion use has to be provided in the shield cover, the shielding wire has an exposed portion which has an extremely large range in the terminal because of the existence of the opening portion 9b, with a disadvantage in that the shielding effect which is an original object is reduced in half.